Miao Qi
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A pancreatic cancer organoid platform identifies an inhibitor specific to mutant KRAS
[ASAP] Identification of Bona Fide RNA Editing Sites: History, Challenges, and Opportunities
Design of Near‐Infrared Nonfullerene Acceptor with Ultralow Nonradiative Voltage Loss for High‐Performance Semitransparent Ternary Organic Solar Cells
An N-substituted asymmetric nonfullerene acceptor SN with an over 40 nm bathochromically shifted absorption compared to Y6 is designed and synthesized. The PM6 : SN-based binary cell exhibits the lowest nonradiative voltage loss of 0.15 eV ever achieved by organic solar cells (OSCs). Benefiting from extended NIR absorption and lowered voltage loss, PM6 : Y6 : SN-based semitransparent (ST)-OSCs, for the first time, achieve a power conversion efficiency of 14 % with an average visible transmittance over 20 %.
Abstract
Semitransparent organic solar cells (ST-OSCs) are considered as one of the most valuable applications of OSCs and a strong contender in the market. However, the optical band gap of current high-performance ST-OSCs is still not low enough to achieve the optimal balance between power conversion efficiency (PCE) and average visible transmittance (AVT). An N-substituted asymmetric nonfullerene acceptor SN with over 40 nm bathochromically shifted absorption compared to Y6 was designed and synthesized, based on which the device with PM6 as donor obtained a PCE of 14.3 %, accompanied with a nonradiative voltage loss as low as 0.15 eV. Meanwhile, ternary devices with the addition of SN into PM6 : Y6 can achieve a PCE of 17.5 % with an unchanged open-circuit voltage and improved short-circuit current. Benefiting from extended NIR absorption and lowered voltage loss, ST-OSCs based on PM6 : SN : Y6 were fabricated and the optimized device demonstrated a PCE of 14.0 % at an AVT of 20.2 %, which is the highest PCE at an AVT over 20 %.
[ASAP] Head to Tail Distortion Wave Characterizes the Enantiomerization of Helicenes
[ASAP] Isopimarane Diterpenoids from the Rhizomes of Kaempferia marginata and Their Potential Anti-inflammatory Activities
Catalytic Enantioselective Cyclopropenation of Internal Alkynes: Access to Difluoromethylated Three‐Membered Carbocycles
Three's a crowd: A highly enantioselective RhII‐catalyzed cyclopropenation reaction of difluorodiazoethane (PhSO2CF2CHN2) with challenging internal alkynes is reported (up to 99 % yield, 97 % ee). Versatile stereoselective transformations of these unique strained cyclopropenes are also demonstrated.
Abstract
Herein we described an efficient RhII‐catalyzed enantioselective cyclopropenation reaction of internal alkynes with a masked difluorodiazoethane reagent (PhSO2CF2CHN2, Ps‐DFA). This asymmetric transformation offers efficient access to a broad range of enantioenriched difluoromethylated cyclopropenes (40 examples, up to 99 % yield, 97 % ee). The synthetic utility of obtained strained carbocycles is demonstrated by subsequent stereodefined processes, including cross‐couplings, hydrogenation, Diels–Alder reaction, and Pauson–Khand reaction.
Antiprotozoal alkaloid principles of the plant family Amaryllidaceae
Publication date: 15 October 2019
Source: Bioorganic & Medicinal Chemistry Letters, Volume 29, Issue 20
Author(s): Jerald J. Nair, Johannes van Staden
Abstract
Protozoan-borne diseases are prominent amongst diseases caused by parasites. Given their alarming morbidity and mortality statistics, there is ever growing interest in new therapies against these diseases. Whilst synthetic drugs such as benznidazole and melarsoprol have had a profound influence on the clinical setup, there has been significant interest in the phytochemical platform to also deliver such drug candidates. The plant family Amaryllidaceae is recognizable for its isoquinoline alkaloids, which exhibit attractive molecular architectures and interesting biological properties. This survey focuses on the antiprotozoal activities of 73 of such substances described in 18 different species of the Amaryllidaceae. Of these, 2-O-acetyllycorine was identified as the most potent (IC50 0.15 μg/mL against Trypansoma brucei brucei). Also considered are structure-activity relationships which have served to modulate activities, as well as the plausible mechanisms that underpin these effects and afford insight to the Amaryllidaceae alkaloid antiprotozoal pharmacophore.
Graphical abstract
Discovery of trans-3-(pyridin-3-yl)acrylamide-derived sulfamides as potent nicotinamide phosphoribosyltransferase (NAMPT) inhibitors for the potential treatment of cancer
Publication date: 15 June 2019
Source: Bioorganic & Medicinal Chemistry Letters, Volume 29, Issue 12
Author(s): Kuojun Zhang, Yong Ni, Jiaxuan Chen, Zhengchao Tu, Xiaoxing Wu, Dong Chen, Hequan Yao, Sheng Jiang
Abstract
Nicotinamide phosphoribosyltransferase (NAMPT) has emerged as a promising target for the discovery of anticancer drugs. Based on NAMPT inhibitor FK866 that has been advanced into phase II trial, we identified a trans-3-(pyridin-3-yl)acrylamide compound 13 incorporating with a biarylsulfanilamide moiety as a new NAMPT inhibitor. Further structure-activity relationship (SAR) exploration led to additional biarylsulfanilamide-derived compounds with high in vitro NAMPT inhibitory potency and antiproliferative activity. In particular, compound 23, the most potent NAMPT inhibitor (IC50 = 5.08 nM), showed single-digit nanomolar antiproliferative activity against DU145, Hela, and H1975 cells with IC50 values of 2.90 nM, 2.34 nM, and 2.24 nM, respectively, and even subnanomolar level against K562, MCF-7, and HUH7 cells with IC50 values of 0.46 nM, 0.23 nM and 0.53 nM, respectively. Our findings provided promising lead compounds for the discovery of more potent NAMPT inhibitors as anticancer drugs.
Graphical abstract
[ASAP] Direct and Catalytic Amide Synthesis from Ketones via Transoximation and Beckmann Rearrangement under Mild Conditions
[ASAP] Mechanism for O–O Bond Formation via Radical Coupling of Metal and Ligand Based Radicals: A New Pathway
Synthesis, antimycobacterial and cytotoxic activity of α,β-unsaturated amides and 2,4-disubstituted oxazoline derivatives
Source:Bioorganic & Medicinal Chemistry Letters, Volume 27, Issue 4
Author(s): Francisco G. Avalos-Alanís, Eugenio Hernández-Fernández, Pilar Carranza-Rosales, Susana López-Cortina, Jorge Hernández-Fernández, Mario Ordóñez, Nancy E. Guzmán-Delgado, Alejandro Morales-Vargas, Víctor M. Velázquez-Moreno, María G. Santiago-Mauricio
The synthesis of six α,β,-unsaturated amides and six 2,4-disubstituted oxazolines derivatives and their evaluation against two Mycobacterium tuberculosis strains (sensitive H37Rv and a resistant clinical isolate) is reported. 2,4-Disubstituted oxazolines (S)-3b,d,e were the most active in the sensitive strain with a MIC of 14.2, 13.6 and 10.8μM, respectively, and the compounds (S)-3d,f were the most active against resistant strain with a MIC of 6.8 and 7.4μM. The ex-vivo evaluation of hepatotoxicity on precision-cut rat liver slices was also tested for the α,β-unsaturated amides (S)-2b and (S)-2d,f and for the oxazolines (S)-3b and (S)-3d,f at different concentrations (5, 15 and 30μg/mL). The results indicate that these compounds possess promising antimycobacterial activity and at the same time are not hepatotoxic. These findings open the possibility for development of new drugs against tuberculosis.
Graphical abstract
Discovery of 2H-Chromen-2-one Derivatives as G Protein-Coupled Receptor-35 Agonists
Synthesis of Lithium Boracarbonate Ion Pairs by Copper-Catalyzed Multi-Component Coupling of Carbon Dioxide, Diboron, and Aldehydes
A novel family of well-defined molecular lithium boracarbonate ion pairs containing a unique boron-implanted cyclic carbonate framework are efficiently synthesized by the highly selective coupling reaction of CO2, bis(pinacolato)diboron, LiOtBu, and a wide range of aldehydes in the presence of an N-heterocyclic carbene copper catalyst.
[Communication]
Béatrice Carry, Liang Zhang, Masayoshi Nishiura, Zhaomin Hou
Angew. Chem. Int. Ed., April 09, 2016, DOI: 10.1002/anie.201602278. Read article